Detecting Daemon Tools

Hi,

a lot of games blacklisting daemon tools and i always wondered how
they actually do this. Well after some reversing i found a very simple
way of detecting by simply try to load the daemon.dll file located
in the windows directory and call the deactivate function for RMPS
emulation and mounting.
But i saw some other programs which deactivate dtools in a different way and i couldn't figure it out how they do that...It seems that
you can gather information about dtools by looking into the registry
but changing names and values didn't work.

Does anyone has some information on different ways how to do that?
I plan to write a small patcher for 100% hiding dtools if this is possible.

thx